. >>> secretary of state hillary clinton is heading back to work next week. she was recovering from a bug you'll recall when she fainted, fell and suffered a concussion. that was three weeks ago. now she's good to go. doctors still want her to wait a little longer before traveling overseas. now, one of the ideas that seems totally obvious and completely inevitable until you realize that somebody had to think of it first. it's something that takes the newest technology, the smartphone, and couples it to one of the oldest, the chariot. the result makes it easier for some to get around town, and others to make a living. tom foreman has the story of uber, a german word, in tonight's "american journey." >> reporter: for 13 years in the crush and crawl of d.c. traffic, robert harrison has made a sometimes difficult living as a limo driver, but a surge of new riders now has him for the first time heading into the holidays with real optimism about his job. >> they have saved the day for us as independent limo drivers. >> reporter: that's the impact? >> that's the imp